Get decimal portion of a number with JavaScript

Question

I have float numbers like 3 2 and 1 6  I need to separate the number into the integer and decimal part  For example  a value of 3 2 would be split into two numbers  i e  3 and 0 2 Getting the integer portion is easy  n   Math floor n    But I am having trouble getting the decimal portion  I have tried this  remainder   n   2    obtem a parte decimal do rating  But it does not always work correctly  The previous code has the following output  n   3 1    gives remainder   1 1  What I am missing here

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A simple way of doing it is    x000D   x000D  var x   3 2  x000D  var decimals   x - Math floor x   x000D  console log decimals     Returns 0 20000000000000018 x000D   x000D   x000D    Unfortunately  that doesn t return the exact value  However  that is easily fixed    x000D   x000D  var x   3 2  x000D  var decimals   x - Math floor x   x000D  console log decimals toFixed 1      Returns 0 2 x000D   x000D   x000D    You can use this if you don t know the number of decimal places    x000D   x000D  var x   3 2  x000D  var decimals   x - Math floor x   x000D   x000D  var decimalPlaces   x toString   split      1  length  x000D  decimals   decimals toFixed decimalPlaces   x000D   x000D  console log decimals     Returns 0 2 x000D   x000D   x000D

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You can use parseInt   function to get the integer part than use that to extract the decimal part  var myNumber   3 2  var integerPart   parseInt myNumber   var decimalPart   myNumber - integerPart    Or you could use regex like   splitFloat   function n      const regex      d       1   d        var m      if   m   regex exec n toString         null           return             integer parseInt m 1              decimal parseFloat  0   m 2

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Although I am very late to answer this  please have a look at the code   let floatValue   3 267848  let decimalDigits   floatValue toString   split      1   let decimalPlaces   decimalDigits length  let decimalDivider   Math pow 10  decimalPlaces   let fractionValue   decimalDigits decimalDivider  let integerValue   floatValue - fractionValue   console log  Float value    floatValue   console log  Integer value    integerValue   console log  Fraction value    fractionValue

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n   Math floor x   remainder   x   1

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var decimal   n - Math floor n    Although this won t work for minus numbers so we might have to do  n   Math abs n      Change to positive var decimal   n - Math floor n

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How is 0 2999999999999998 an acceptable answer   If I were the asker I would want an answer of  3   What we have here is false precision  and my experiments with floor     etc indicate that Javascript is fond of false precision for these operations   So I think the answers that are using conversion to string are on the right track    I would do this   var decPart    n     split      1     Specifically  I was using  100233 1 and I wanted the answer   1

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float a 3 2  int b  int a     you ll get output b 3 here  int c  int a-b     you ll get c  2 value here

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Use 1  not 2   js gt  2 3   1 0 2999999999999998

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If precision matters and you require consistent results  here are a few propositions that will return the decimal part of any number as a string  including the leading  quot 0  quot   If you need it as a float  just add var f   parseFloat  result   in the end  If the decimal part equals zero   quot 0 0 quot  will be returned  Null  NaN and undefined numbers are not tested  1  String split var nstring    n    quot  quot        narray    nstring split  quot   quot        result     quot 0  quot      narray length  gt  1   narray 1     quot 0 quot      2  String substring  String indexOf var nstring    n    quot  quot        nindex    nstring indexOf  quot   quot        result     quot 0  quot     nindex  gt  -1   nstring substring nindex   1     quot 0 quot     3  Math floor  Number toFixed  String indexOf var nstring    n    quot  quot        nindex    nstring indexOf  quot   quot        result      nindex  gt  -1    n - Math floor n   toFixed nstring length - nindex - 1     quot 0 0 quot     4  Math floor  Number toFixed  String split var nstring    n    quot  quot        narray    nstring split  quot   quot        result     narray length  gt  1    n - Math floor n   toFixed narray 1  length     quot 0 0 quot     Here is a jsPerf link  https   jsperf com decpart-of-number  We can see that proposition  2 is the fastest

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Here s how I do it  which I think is the most straightforward way to do it   var x   3 2  int part   Math trunc x      returns 3 float part   Number  x-int part  toFixed 2       return 0 2

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I had a case where I knew all the numbers in question would have only one decimal and wanted to get the decimal portion as an integer so I ended up using this kind of approach   var number   3 1      decimalAsInt   Math round  number - parseInt number     10      returns 1   This works nicely also with integers  returning 0 in those cases

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Language independent way   var a   3 2  var fract   a   10   10  10    0 2 var integr   a - fract    3   note that it correct only for numbers with one fractioanal lenght

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This function splits float number into integers and returns it in array   x000D   x000D  function splitNumber num      num     0    num  match    0-9      0-9   0-9           return     num 1     num 3        console log splitNumber 3 2             3  2   console log splitNumber 123 456         123  456   console log splitNumber 789             789  0   console log splitNumber  test           0  0   x000D   x000D   x000D   You can extend it to only return existing numbers and null if no number exists   x000D   x000D  function splitNumber num      num         num  match    0-9      0-9   0-9           return  num     num 1    null  num  amp  amp  num 3      undefined     num 3    null      console log splitNumber 3 2             3  2   console log splitNumber 123 456         123  456   console log splitNumber 789             789  null   console log splitNumber  test           null  null   x000D   x000D   x000D

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I am using   var n   -556 123444444  var str   n toString    var decimalOnly   0   if  str indexOf         -1      check if has decimal     var decimalOnly   parseFloat Math abs n  toString   split      1        Input  -556 123444444  Result  123444444

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I like this answer https   stackoverflow com a 4512317 1818723 just need to apply float point fix function fpFix n      return Math round n   100000000    100000000     let decimalPart   2 3   1    0 2999999999999998 let correct   fpFix decimalPart     0 3  Complete function handling negative and positive function getDecimalPart decNum      return Math round  decNum   1    100000000    100000000     console log getDecimalPart 2 3       0 3 console log getDecimalPart -2 3       -0 3 console log getDecimalPart 2 17247436       0 17247436  P S  If you are cryptocurrency trading platform developer or banking system developer or any JS developer    please apply fpFix everywhere  Thanks

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Depending the usage you will give afterwards  but this simple solution could also help you    Im not saying its a good solution  but for some concrete cases works  var a   10 2 var c   a toString   split      console log c 1     2    True console log c 1      2     False   But it will take longer than the proposed solution by  Brian M  Hunt   2 3   1  toFixed 4

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Math functions are faster  but always returns not native expected values  Easiest way that i found is    3 2     replace    - d

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The following works regardless of the regional settings for decimal separator    on the condition only one character is used for a separator   var n   2015 15  var integer   Math floor n  toString    var strungNumber   n toString    if  integer length     strungNumber length    return  0   return strungNumber substring integer length   1     It ain t pretty  but it s accurate

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After looking at several of these  I am now using     var rtnValue   Number 7 23   var tempDec     rtnValue   1  - Math floor rtnValue   toFixed 2

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A good option is to transform the number into a string and then split it      Decimal number let number   3 2      Convert it into a string let string   number toString        Split the dot let array   string split           Get both numbers    The     sign transforms the string into a number again let firstNumber     array 0      3 let secondNumber    array 1      2   In one line of code  let  firstNumber  secondNumber      number toString   split      0    number toString   split      1

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You could convert it to a string and use the replace method to replace the integer part with zero  then convert the result back to a number     var number   123 123812      decimals    number toString   replace            0

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The best way to avoid mathematical imprecision is to convert to a string  but ensure that it is in the  quot dot quot  format you expect by using toLocaleString   x000D   x000D  function getDecimals n         Note that maximumSignificantDigits defaults to 3 so your decimals will be rounded if not changed    const parts   n toLocaleString  en-US     maximumSignificantDigits  18    split        return parts length  gt  1   Number  0     parts 1     0    console log getDecimals 10 58   x000D   x000D   x000D

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You could convert to string  right   n    n       split

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Floating-point decimal sign and number format can be dependent from country       so independent solution  which preserved floating point part  is    getFloatDecimalPortion   function x        x   Math abs parseFloat x        let n   parseInt x       return Number  x - n  toFixed Math abs     x  length -     n  length - 1             it is internationalized solution  instead of location-dependent   getFloatDecimalPortion   x   gt  parseFloat  0       x       split      1       Solution desription step by step    parseFloat   for guaranteeing input cocrrection Math abs   for avoiding problems with negative numbers n   parseInt x  for getting decimal part x - n for substracting decimal part We have now number with zero decimal part  but JavaScript could give us additional floating part digits  which we do not want So  limit additional digits by calling toFixed   with count of digits in floating part of original float number x  Count is calculated as difference between length of original number x and number n in their string representation

[javascript] Get decimal portion of a number with JavaScript

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